As an exterior heat exchanger used for a heat pump system for vehicle air-conditioning and the like, a subcool system condenser provided with a main core (condenser core) portion for condensing a refrigerant by heat exchange with air, a receiver tank into which the refrigerant having passed through the main core portion flows, and a subcool core portion for completely liquefying the liquid refrigerant having passed through the receiver tank by supercooling it by heat exchange with the air is disclosed (see Patent Document 1, for example).
The above-described main core portion and the subcool core portion are constituted by a plurality of tubes allowing a pair of header tanks arranged at an interval in a state in parallel with each other to communicate with each other and fins arranged between adjacent tubes, for example.